The present invention relates generally to light polarization systems, and more particularly to an improved system and method for reducing glare from a plurality of light sources via an unmatched polarization system.
The disabling effect of headlight glare is a significant highway safety problem. Headlights of oncoming cars may be blindingly bright, for example. This may cause objects of low illumination to practically disappear from the driver""s field of visibility and may also create driving fatigue. Furthermore, headlight glare may cause annoyance and discomfort to the driver and occupants of a vehicle at night. Although the bulk of highway travel occurs during daylight hours, most highway fatalities occur at night. Consequently, headlight glare may be a factor in many crashes occurring at night.
With the advent of halogen beams, daytime running lamps and eye-level headlights in vehicles such as vans, minivans, light trucks, and Sports Utility Vehicles (xe2x80x9cSUV""sxe2x80x9d), the problem of headlight glare has gotten worse. These problems may persist as higher intensity headlights come into even greater use. Drivers are not only exposed to headlight glare directly from oncoming traffic, but, also from rearview mirrors. The greater number of vans, minivans, light trucks and SUV""s has resulted in headlights that are mounted higher than those of a standard auto, increasing the likelihood of glare directly to the eyes of drivers of today""s standard cars- either through the front windshield and/or via the rearview mirror. Moreover, many cars, vans, minivans, light trucks and SUV""s may have xe2x80x9cfog lightsxe2x80x9d installed, as well as regular headlights, and many of these lights may be improperly aimed.
Increasingly, headlights may become brighter as a result of changes to the U.S. Federal Motor Vehicle Safety Standard governing headlights (FMVSS 108). Thus, today""s headlights are brighter and have a wider beam pattern than older headlights of ten or twenty years ago. Presently, U.S. Federal Motor Carrier Safety Regulations require headlights to be mounted between 22 and 54 inches above the roadxe2x80x94a considerable variation. Therefore, with brighter lights, wider beam patterns, and diverse headlight mounting requirements, problems resulting from glare will likely continue to increase.
Headlight glare may also cause fatigue and eye strain for toll takers in toll booths during nighttime hours, and may create problems for people living in homes at the end of a cul-de-sac and/or on a street perpendicular to oncoming traffic, for example. Additionally, joggers, bicyclists and/or pedestrians on the side of a road may be temporarily blinded by an oncoming vehicle""s headlights such that they may not be able to see obstacles in or on their path causing them to stumble and to possibly receive bodily injury.
Methods to reduce glare and other light glare by use of optical filters has long been known. For example, these methods may include linearly polarized transmitters placed on or near headlights paired with matching linearly polarized analyzers placed on the windshield and/or visor and/or glasses. Also, circularly polarized transmitters paired with matching circularly polarized analyzers is known. Similarly, elliptically polarized transmitters paired with matching elliptically polarized analyzers is known. Unfortunately, a problem associated with these methods is that while they may reduce headlight glare of oncoming cars, they may also substantially reduce the illumination from the driver""s own headlights, thus producing a dangerous loss of dim light vision and/or impairing the driver""s visibility of the roadway.
Another problem associated with paired matching polarizers (e.g., linear/linear, circular/circular) is that they may substantially extinguish and/or eliminate too much of an oncoming vehicles"" headlight luminosity, making it difficult to see oncoming vehicles. Additionally, another problem is that a driver may not be able to see the illumination beam of an oncoming vehicle not yet visible on the other side of a hill or a curve which may serve as an advance warning of that vehicle""s approach.
Optical filter lenses on eyeglasses, such as a yellow tint, are not very effective against headlight glare. Some xe2x80x9cnight drivingxe2x80x9d glasses may even add an ultraviolet light filter, which is not particularly relevant at night, since UV light is generally produced by the sun. If the night driving glasses are xe2x80x9cblue-blockerxe2x80x9d lenses which filter available blue light, they may produce severe color distortion which may be a serious hazard when driving at night.
In view of the above problems associated with convention matched pair polarization systems, a system and method is needed that mitigates an oncoming vehicles"" headlight glare, does not interfere with one""s ability to clearly see the headlights of the oncoming vehicle and/or the illumination beam of a vehicle on the other side of a hill or a curve and, yet, at the same time does not substantially reduce the illumination from the driver""s own headlights.
The present invention relates to a system and method for reducing glare, yet, mitigating visibility losses associated with conventional polarization systems. In accordance with the present invention, a glare reduction system is provided wherein glare from a plurality light sources is mitigated via an improved polarization system while clarity of vision from the light sources may be increased over conventional systems. For example, the present invention enables a driver to clearly see headlights of oncoming vehicles while mitigating the effects of the oncoming vehicle""s headlight glare. This may benefit a driver and/or occupant in a second vehicle, a jogger, worker and/or pedestrian on the side of the road, and/or a person in a stationary location such as a toll booth or home. Furthermore, the present invention may be applied to substantially any light source to reduce glare and improve visible clarity. For example, glare from stadium illumination floodlights may be mitigated as viewed by persons in attendance while not substantially reducing the illumination reflected back from stadium field of play. Also, glare from sources such as ambient light on a computer monitor, television, VCR and/or DVD screen may be mitigated while not substantially reducing the illumination coming from the screen.
More specifically, the present invention provides an unmatched (e.g., circular/linear, elliptical/linear) polarization system to achieve glare reduction and improve visibility losses associated with conventional polarization systems. For example, the present invention may provide a linear polarization analyzer associated with a viewer in combination with a circular polarization transmitter associated with a light source. When viewed from the analyzer, glare from the light source may be mitigated without substantial dimming of the source. In contrast to conventional matched polarization systems wherein a pair of linearly matched systems, circularly matched system, and/or elliptically matched systems may be employed, the present invention does not substantially sacrifice light intensity for the sake of reducing associated glare. Thus, a substantial improvement may be achieved over conventional systems. Additionally, the present invention may provide the above benefits at lower costs than associated with systems consisting of two matched circular polarizers and/or two matched elliptical polarizers.
To the accomplishment of the foregoing and related ends, the invention then, comprises the features hereinafter fully described. The following description and the annexed drawings set forth in detail certain illustrative aspects of the invention. These aspects are indicative, however, of but a few of the various ways in which the principles of the invention may be employed and the present invention is intended to include all such aspects and their equivalents. Other advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the drawings.